Casey Versus The Creepy Twins
by dark-adrenalynn
Summary: Post Season 2 of Chuck and a lot after the BDM. While on a mission to discover what their enemies are up to, Team Bartowski discovers that they've been using time travel to find someone capable of holding an intersect. Intel and destroy becomes a rescue mission, but they wind up with more than they bargained for.


**Disclaimer:** I do not own anything related to Chuck or Firefly, unless you mean some pictures and good memories from a Browncoat Ball and a few DVDs.

**Note:** Post-Season Two and _Serenity._ (By a lot). This is a crazy crossover, and I almost apologise.

* * *

It was a dangerous mission, but a needed one. Those were all too common, Chuck had found since becoming the Intersect. This particular mission wasn't supposed to be as dangerous as it was, but when did anything ever stay as simple as it seemed in Castle? Chuck was posing as an incredibly gifted scientist in what was thought to be a simple rebel militia group. What he had actually gotten himself into was the center of a Ring lab, where a bunch of "evil eggheads" as Casey eloquently put it, were trying to create an Intersect by using a machine that somehow teleported people who might be able to contain the knowledge into their labs.

The very disturbing thing was that the Ring was using children, hoping that if they found an "appropriate" brain early enough, they could train up their intersect into a perfect agent by adulthood. A super soldier. The screams from failed Intersect children made his stomach clench, and so, after he had knocked out two other doctors, he called in Casey and Sarah.

"How can they use children?" Chuck asked into his watch as he waited for his partners to appear. "It's just...it's wrong." He shuddered.

"The Ring specializes in wrong, Chuck." Sarah said, soothingly. A moment after her voice came over the communicator, she appeared through one of the glass doors of the place, followed by Casey. She had been uncomfortable letting him go in undercover in the first place, but he was the one who fit in the best, and nothing had happened.

"Still, we have to rescue the kids their holding now." Chuck said, concerned.

"Our orders are to destroy the machine that they've been using, not a rescue mission, Bartowski." Casey pointed out, though the expression on his face showed that he might take less convincing than expected. Hurting children _bothered _Casey, for all his missions had sometimes required it, it was always collateral damage, not like this.

"Well, they're all in the same room." Chuck said. "The lead scientist is with them now, in the summoning and interrogation room." He had never been allowed in, but the bugs he had planted had given him the codes needed, and feeling more and more like a spy, he led them to the room, mentally patting himself on the back.

"We don't bust in, moron." Casey said, resisting the urge to smack Chuck. "Not if we can find out what they're planning from the other side. Is it built like Castle's interrogation rooms? Can we get eyes and ears on what they're saying from the other side?"

"Yes, but we need to rescue..." Casey didn't let him finish and pulled him over to the observation room. "Just put in the damn code, Bartowski."

Chuck did as he was told, mostly because when Casey said things like that, you didn't fight him. The three of them slipped into the observation room, where they could plainly see two girls facing them, talking or, not-talking, to the lead scientist, who was facing away from them.

"Now, girls, you don't have to make this difficult." The doctor said easily. "I don't want to hurt you anymore. What would your mommy and daddy say if they knew you refused to answer a few harmless questions and let yourself get hurt?"

The girls blinked and replied in one voice. "Good girls."

The doctor had obviously not expected that, and he frowned. He picked up what looked to be a wand or cylinder of some type and passed it over the two girls, causing each to tense, and the one on the right to cry out in pain. "Now, let's try this again." He said easily.

"_Jian te de gui!_" The one on the right hissed at him. The one on the left however, looked past the doctor at the window, staring right at Team Bartowski as if she could see them.

"_Bi zui, jie jie._" The one on the left said softly, but loud enough for them to hear in the observation room. She then addressed the doctor. "We will answer your questions. We would like to help." Her twin looked ready to protest, but a look silenced her.

"Good girls." The man replied happily. "Now, what are your names?"

"Phoebe." Said the one on the right, looking irritated.

"Lux." Replied the other.

"And you are how old?" The doctor said, as he noted the names on his pad.

"Six." They answered together.

"And you were born where?"

"I was born on Phobos." Phoebe replied. "But Lux was born vesselside, because Lux was troublesome."

"And what year are you from?" The doctor asked, making a few more notes, and startling the three spies in the observation room.

"2534." They replied together, in perfect unison. Then Lux paused and tilted her head. "Yes, we are the furthest you've grabbed with your machine. All the other children were from within this century, but they were all failures. None had a proper brain. There was so much blood, so much waste. You thought by setting the machine to the extreme you could find someone further along the evolutionary line, who could hold your Intersect. But manipulating time and space is complicated, and in taking us you broke your machine."

The man was startled and he dropped his pen. It rolled across the table and stopped in font of the twin on the right, Phoebe. She stared at it for a moment and then gave the doctor an odd and very eerie grin. "You're gonna die." She informed him, almost gaily. "Bullet in the brainpan."

The doctor was staring at them in horror, as if wondering what his meddling had pulled into his time. The look was mirrored in Chuck from the observation rooms. "Their the creepy twins!" he declared. "The creepy twins from all the horror movies and books!"

As if answering him, the twin on the left grumbled. "Not creepy." The twin on the right looked at her, and realised what was happening, or near enough, and shrugged. He was so fascinated by the byplay between the sisters, little six year olds who sometimes sounded like kids, and sometimes spoke like adults, that seemed to hear him despite the soundproofing, that he missed Casey's big gun being brought out, and a shot being fired, until the one on the right pulled her sister down, just before the big man pulled the trigger.

Just like she said, the doctor slumped forward, dead, from a head-shot.

"Eww." Said Phoebe, as she came up again. "Brain bits." She made a face and looked a little green, while her sister just sat up and fixed her hair.

With the scientist dead, all three members of Team Bartowski moved into the interrogation room. Sarah made a beeline for the children, while a distinctly nervous Chuck moved more towards the machine, and John Casey headed to the body to confirm the kill. something a bit unnecessary, but since Bryce Larkin and the habit of Fulcrum to not stay dead, he did it when he could.

"Daddy?" One of the twins said, the one on the left, the one with the long hair, her blue eyes fixed on Casey, head tilted similarly to how she had tilted it at the scientist. Her sister did not show her restraint and instead, threw herself bodily onto Casey's chest with an excited: "_Ba ba!_"


End file.
